1. Field of Invention
This invention relates to color-appearance systems, specifically to the organization of colors for use by artists.
2. Prior Art
Color-appearance systems are plans by which colors may be defined, arranged, displayed, compared, selected, and in some cases, formulated. Having a color chart, swatch book, or other tabulated reference of displayed color on hand is a convenient way of examining what colors are available. While the human eye is capable of perceiving color with great sensitivity, our color memory is short-lived. Being able to see, compare, and match elements of a color gamut directly can aid an artist or designer in accurately conceiving and assembling color relationships, and in realizing the limits of a specific color medium. Presently there are no color-appearance systems which adequately meet both the traditional and technological needs of today's fine artist. There are ink-based color matching systems tailored to the printing industry and there are pigment-based systems used to specify industrial color matches, but both of these types of systems are too large and complex to be of practical use to the individual working with color on a smaller scale. Also, because these systems are geared toward mass-production colorants, they are not easily adapted to the unique, more expensive, lightfast coloring materials used by artists.
Beyond some published color-mixing recipes and colored paper assortments, no tools are available to aid the artist in effectively dealing with the wide variety of color choices and new media he or she currently encounters, particularly in the realm of computer graphics. Traditional color charts and diagrams, most notably circles and constant-hue charts (FIGS. 1 to 4-B), continue to be useful in providing general color-organizing concepts but often bewilder the artist with a multitude of nonessential color differences.
Personal computer graphics software systems are commercially available and have become increasingly popular with artists, photographers, and other users of digital imaging. A general-purpose graphical user interface (GUI) as used in various computer operating-systems, such as those sold under the trademark, Windows by Microsoft Corporation of Redmond Wash., or Macintosh by Apple Computer, Incorporated of Cupertino Calif., as well as a specialized GUI used within many paint and illustration programs, permits the programmer to designate certain portions of the computer screen as “buttons” which may be “pushed,” or color display areas wherein a color may be chosen, or means for displaying “menus” which present lists of actions which can be taken. These on-screen tools are operated by positioning and actuating a pointer device, such as a mouse. When a button, color display area, menu, or other selection device is so actuated, a window is displayed, a color is selected, or some other computer command or interaction is selected and implemented. Choosing a color within this type of GUI is not necessarily easy, however, since the color selection devices (called “color pickers”) usually comprise a representative sampling of the over 16 million colors that can be displayed on the computer screen (FIGS. 5-A, 6, and 8-A). To obviate the need to choose from such an overwhelming gamut, another type of color selector in common use is a color swatch set or color palette (FIGS. 5-B, 7, 8-B, and 9). However, the known color palettes and swatch sets, containing relatively smaller assortments of discrete color elements, are not organized in formats with which most artists are comfortable.
The capabilities of GUI programming have become quite sophisticated. For instance, one illustration program (marketed under the trademark CorelDRAW 8 by Corel Corp. of Ottawa, Ontario, Canada) provides a color picker that allows a user to select a color in the normal manner, by placing a mouse's pointer (or cursor) over a color element and “clicking” (i.e., pressing down and quickly releasing a button on the mouse). However, it also has a feature in which the user depresses the button on the mouse and continues to hold it down. This special action (known as a “mouse press”) triggers the display of a “popup” palette 160 (FIG. 9) of neighboring colors, allowing the examination and further selection of color variations very close to the originally selected color. The intention of this device is to provide additional ease of use; what is missing is a recognizable organizational framework for artists.
Computer color pickers are currently offered for adapting the arrangement of a monitor's light-based colors to artists' use. For example, the Painter's Picker, marketed by Old Jewel Software of Windsor, N.Y., provides an alternatively arranged color wheel in which yellow is shifted from its conventional position of 60° distance from red, to a position 120° equidistant from both red and blue, thus replicating the positions of the three primaries of a traditional, artist's pigment-based color wheel. However the 360° of this “artistic” RGB color wheel fails to provide a perceptually even distribution of hue (FIG. 36). It also presents its hue gamut as a smooth, contiguous blend from which it is difficult to distinguish and select particularly desired hues.
While there are earlier examples of circular color organizations, Newton's (FIG. 1) is generally acknowledged to be the first color circle to accurately present the sequence of the visible spectrum. Published in his Opticks, London 1704, his simple diagram is the precursor to a host of two- and three-dimensional color charts, models, and maps. Of these, three significant circular systems, directed to the artist's use of color, are those of Chevreul, Ostwald, and a color system currently marketed under the trademark Munsell by GretagMacbeth, of New Windsor, N.Y.
Chevreul's pioneering work of 1839, The Law of Simultaneous Contrast of Colors, contains one of the most influential color circles in history (FIG. 2). Based upon the three subtractive (or pigment-based) primaries (red-yellow-blue), Chevreul's circle places complementary colors opposite one another. Because it is subdivided into 72 contiguous hues it is an awkward organizational tool.
Ostwald's color system (FIGS. 3-A and 3-B), introduced in 1917, places 24 hues spaced in equidistant steps on a circular chart (FIG. 3-A). While simpler than Chevreul's color circle, its adherence to Hering's four-color scheme of “psychological” primaries (red-yellow-green-blue) makes the Ostwald arrangement relate more closely to human color vision than to mixtures of pigments.
The widely accepted Munsell color system (FIGS. 4-A and 4-B) has evolved from U.S. Pat. Nos. 824,374 to Munsell (1906) and 1,617,024 to Munsell (1927), which disclose circular and constant-hue color charts, and a system of color notation. It is a globally recognized standard for providing a means of color specification. However, in order to express the spectrum with only ten basic hues, its hue circle (FIG. 4-A) radically compresses the “red-orange-orange-yellow-orange” range into a single “yellow-red” hue. Consequently, the Munsell color system fails to adequately reflect the full range of pigments available to artists.
Commercial color-appearance systems often build up large numbers of component color samples by basing their range upon the ability of the human eye to differentiate color according to what is called “just noticeable difference.” That is, as soon as a color becomes just noticeably different, either in value, saturation, or hue, it becomes an additional color element in the system. (Estimates of the number of color variations that the human eye can differentiate range between 17,000 and 10 million.) For example, the Japan Color Research Institute, Tokyo (1978), provides a color reference system sold under the trademark Chroma Cosmos 5000. This is one of several color reference systems or multi-paged atlases which, by reason of their large quantity of finely-differentiated color elements (numbering in this case 5000), are too complex for general artistic use. Other similar color systems widely accepted in Europe include those sold under the trademark RAL Design System, from the German Institute for Quality Assurance and Certification e.V. of Sankt Augustin, Germany with 1688 colors, and under the trademark Natural Color System, from The Scandinavian Colour Institute of Stockholm, Sweden with 1750 colors.
A color matching and specification system aimed at decorative artists and craftspeople, currently marketed under the trademark TCS Color Matching System by Tru-Color Systems, Inc. of Danville, Ind., USA, diagrams the visible spectrum divided into 108 contiguous hues on a color circle. Organized into the 12 traditional artists' color families, with 3 additional color families (black, white, and brown) organized separately, the software implementation of the system proposes several methods of achieving harmonious color schemes. By subdividing the hues of each of its color families into 9 contiguous steps of both value and saturation, the TCS system contemplates a potential assortment of 10,208 separately identified colors.
Recognizing the impracticality of choosing visually from among the over 16 million colors available in the typical computer program, U.S. Pat. No. 5,903,255 to Busch et al. (1999) discloses a hexagonal-honeycomb color picker aimed at simplifying computer color selection. Since users generally prefer to select colors by seeing them, rather than by specifying numerical values, and since the smoothly-blended colors presented by some computer programs for color selection have the disadvantage of not allowing the user to visualize or pick a discrete color, the system of this patent utilizes a diagram of honeycomb-cells for displaying a small subset of predetermined colors. The subset, however, comprises only 144 distinct colors, and such an abridged representation of the computer color gamut, while suitable for selecting colors for maps, charts, and business graphics, is inadequate for artistic use.
U.S. Pat. No. 5,254,978 to Beretta (1993) discloses a reference color selection system which creates palettes of calorimetrically measured colors, including artists pigments, and arranges them in a database for access and use in computer graphics programs. The interface with which colors are selected, however, is not formatted in an arrangement of color familiar to artists. This system also takes into account that some strongly saturated artists' colors will fall outside the calibrated monitor's gamut, and their coordinates will need to be modified with suitable gamut mapping or clipping algorithms to bring them back within the boundary of what can be displayed on screen with relative accuracy.
Another U.S. Pat. No. 5,311,212 to Beretta (1994), shows a system, typical of many other prior-art systems, that automatically generates computer color choices for unskilled color users. This patent is incorporated by reference for providing an excellent exposition of the computing environments and methods in which digital color palettes are referenced by onscreen color selection devices, in this case according to algorithms for choosing and displaying harmonious color schemes. However the formulaic theory of color harmony on which these algorithms is based provides only trite color combinations unsuited to most fine arts applications.
In contrast to large, complicated color systems, many patents have issued which organize simplified arrangements of artists' colors according to a single diagram. U.S. Pat. No. 1,805,520 to Grumbacher (1931), for example, is a watercolor palette which places the three subtractive primaries (red-yellow-blue) on a twelve-hued circle. While an efficient format for organizing basic, wet-media elements, this palette has no provision for arranging more comprehensive color assortments.
Another simple palette, disclosed in U.S. Pat. No. 5,209,664 to Wilcox (1993), proposes that the three traditional, subtractive primaries are inadequate for color mixing. Postulating that red, yellow, and blue are never true primaries, but that each always exhibits either a warm or cool bias, Wilcox offers a six-primary format as a more comprehensive arrangement, which overcomes such biases. Hence his palette accommodates three pairs of “biased” primary colors, i.e., an orange-red and a violet-red pair, an orange-yellow and a green-yellow pair, and a green-blue and a violet-blue pair. No accommodation is made, however, for including median primaries, that is primaries which have no perceptible warm or cool bias. Also, as in the Grumbacher patent, supra, and other similar palettes, no provision is made for arranging larger color assortments.
Of all patents which have issued addressing color aesthetics and artistic use, a few are directed specifically to the organization and production of artists' colorants:
For example, U.S. Pat. No. 918,068 to Maratta (1909), discloses color charts presenting the spectrum of artists' pigments in mixtures of two saturation levels. These charts aid the artist in the selection of harmonious color combinations. Maratta's self-manufactured line of paints, containing 24 equally-spaced hues (red, red-red-orange, red-orange, red-orange-orange, orange, etc.), and accompanying formulas for achieving color harmony, was advocated by a renowned painting teacher, Robert Henri. The Maratta system enjoyed a brief period of popularity, but was eventually rejected by Henri's students as being too technical.
U.S. Pat. Nos. 3,628,260 to Jacobson (1971) and 3,722,109 to Jacobson (1973) disclose a color mixing system which proposes that predicted color results are most easily achieved by mixing like values of colors together. A 35-color assortment of paints based on this patent was manufactured in both oil and acrylic and marketed under the trademark Modular by Permanent Pigments, a division of Binney & Smith, Inc., of Cincinnati, Ohio. It failed commercially, largely because of the perception that buying 35 premixed values of just ten different hues was neither economical nor convenient. The chief ingredient in many of the paints was white or gray, and the complete system required an unnecessary number of paint tubes e.g., four tubes of blue, where one would do.
More recently, an approach to artists' colors is proposed by U.S. Pat. Nos. 5,033,963 to Bourges (1991) and 5,161,974 to Bourges (1992) which disclose, respectively, a 20-hued color system, and an improvement in which its colors lie entirely within the gamut of standard four-color offset printing. Consequently, to insure reliable color reproduction, this system requires the artist to abandon the broad gamut of traditional pigments, and use instead 20 hues, all derived from the four process colors (cyan, magenta, yellow, and black).
In my previous U.S. Pat. No. 5,860,518 (1999) 1 disclose a computer-displayed color picker based on a compartmented pastel case. In arranging pastel colors within each color compartment, I suggest that the introduction of minor warm and cool variations of the basic hue be allowed in order to add vitality to the resulting color assortment, however I describe no system for defining the extent of these variations.
Other prior-art color systems, charts, and color atlases share many of the general disadvantages cited above. These include needless complexity (or, on the opposite hand, oversimplification), barely distinguishable color variations, inflexible organization, and a restrictive adherence to the limitations of a particular medium or technology. A color-appearance system for modern, practical artistic use should, however, neither overwhelm by sheer number, or subtlety, of choices, nor surrender to the limitations of standard color display and reproduction processes, but instead offer a concise, flexible format for organizing a representative sampling of the wider color universe present in whatever color medium the artist has chosen.
The color system of the present invention addresses these goals and others by redefining the artist's twelve color families, and providing an improved organizational format for traditional coloring materials as well as the colors produced by current technologies.